Question

The length, breadth and height of a hall 8 m, 10m,4m respectively and the hall has one door of area 3m*1.5m.Find the cost of painting by the wall at the rate of rs200 per square metre

Answer 1

Question : -

The length, breadth and height of a hall is 8 m, 10 m, 4 m respectively and the hall has one door of area 3 m $\times$ 1.5 m. Find the cost of painting of the wall at the rate of Rs. 200 per square metre.

Answer : -

Step-by-step explanation : -

Given that,

Length = 10 m

Breadth = 8 m

Height = 4 m

Length of door = 3 m

Breadth of the door = 1.5 m

To find,

The cost of painting the wall.

First of all, we've to find the lateral surface area of the room. As the room is in the shape of a cuboid. Therefore,

Lateral surface area of the room = 2h(l+b)

Lateral surface area of the room = $2 \times 4 (10\:m+8\:m)$

Lateral surface area of the room = $2 \times 4 (18\:m)$

Lateral surface area of the room = $8\:m (18\:m)$

Lateral surface area of the room = 144 m^2

But we've to find the cost of painting the walls, but there is also a door in one of the wall.

We've to find the surface area of the door and then we've to subtract it from the lateral surface area of the room. So that, we'll get the area for painting thw walls of the room.

Area of the door,

Area of the door = lb

Area of the door = 3 m $\times$ 1.5 m

Area of the door = 4.5 m^2

Area of the walls to be painted = lateral surface area of the room - surface area the door.

Area of the wall to be painted = 144 m^2 - 4.5 m^2

Area of the walls to be painted = 139.5 m^2

Now, we'll multiply the area and the rate to get the cost of painting the walls.

Cost of painting the walls = area $\times$ rate

Cost of painting the walls = 144 m^2 $\times Rs. 200 /m^2$

Cost of painting the walls = ₹ 28,800

Answer 2

Answer:

Step-by-step explanation:

Given that,

Length = 10 m, Breadth = 8 m, Height = 4 m

Length of door = 3 m, Breadth of the door = 1.5 m

First of all, we've to find the lateral surface area of the room. As the room is in the shape of a cuboid. Therefore,

Lateral surface area of the room = 2h(l+b) m^2

Lateral surface area of the room = 2x4(8+10) m^2 = 8(18) m^2

Lateral surface area of the room = 144 m^2

We've to find the surface area of the door and then we've to subtract it from the lateral surface area of the room.

Area of the door = lb

Area of the door = 3 m x 1.5 m

Area of the door = 4.5 m^2

Area of the walls to be painted = lateral surface area of the room - surface area the door.

Area of the wall to be painted = 144 m^2 - 4.5 m^2

Area of the walls to be painted = 139.5 m^2

Now, we'll multiply the area and the rate to get the cost of painting the walls.

Cost of painting the walls = 139.5 m^2  X Rs.200/m^2  =  Rs. 27,900